Simrad EQ 55 Dokumentacja Pobierz pdf (Strona 43)

It is of profound importance for good performance of the EQ32 MKII

that the water flowing over the transducer be free of bubbles and aera-

tion. If the transducer face is clean but the performance degrades with in-

creasing vessel speed, then aeration of the water flowing under the

transducer may be the cause of the poor performance.

Due to the varying design of ship’s hulls and different operating speeds,

there can be great variation in the amount of air bubbles which are car-

ried beneath the hull. These bubbles tend to be carried close to the hull as

they pass aft. For this reason, it is desirable for the transducer to be

mounted on a fairing block which holds the transducer away from the

hull and which directs the flow of aerated water around the sides of the

transducer rather than over the face of the transducer.

On deep keeled vessels, care must be taken to ensure that the transducer

beam wil not be blocked by any part of the keel. Although the appropri-

ate mounting location that meets all requirements depends on the type of

vessel and its normal operating speeds, a practical choice is usually some-

where between one third and one half of the vessel’s water line length

from the bow. Levelling blocks may be designed accordingly to meet

this requirement.

F The more the transducer protrudes from the hull, the better the results

will be.

Particularly the lower frequency operation, interference from propeller

noise can be a significant problem. This can be seen as an increase in the

’noise’ on the echosounder display when the propeller speed is increased.

To help reduce this, the transducer’s mounting face may be angled

slightly forward on the order of 5° for the 50 kHz transducers and 3° for

the 200 kHz transducers. The goal is to incline the transducer so that a

line of sight along the transducer’s radiating surface passes below the

propeller.

F Keeping the propeller clean and free of any nicks or roughness will as-

sist in minimizing interference from propeller noise due to cavitation.

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Simrad EQ 55 Dokumentacja Strona 43